extensions: Introduce a fake ExtensionsClient implementation.

extensions/test/test_permission_message_provider.cc

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "extensions/test/test_permission_message_provider.h"
+
+namespace extensions {
+
+TestPermissionMessageProvider::TestPermissionMessageProvider() {
+}
+
+TestPermissionMessageProvider::~TestPermissionMessageProvider() {
+}
+
+PermissionMessages TestPermissionMessageProvider::GetPermissionMessages(
+    const PermissionSet* permissions,
+    Manifest::Type extension_type) const {
+  return PermissionMessages();
+}
+
+std::vector<base::string16> TestPermissionMessageProvider::GetWarningMessages(
+    const PermissionSet* permissions,
+    Manifest::Type extension_type) const {
+  return std::vector<base::string16>();
+}
+
+std::vector<base::string16>
+TestPermissionMessageProvider::GetWarningMessagesDetails(
+    const PermissionSet* permissions,
+    Manifest::Type extension_type) const {
+  return std::vector<base::string16>();
+}
+
+bool TestPermissionMessageProvider::IsPrivilegeIncrease(
+    const PermissionSet* old_permissions,
+    const PermissionSet* new_permissions,
+    Manifest::Type extension_type) const {
+  return false;
+}
+
+}  // namespace extensions